Document Rec MLX HTTP output budgets and ignored reasoning options

README.md

@@ -27,6 +27,26 @@ rec launch pi
 rec launch opencode
 ```
 
+### HTTP output budgets in Rec MLX v0.1.0
+
+For OpenAI-compatible HTTP requests, set `max_tokens` or `max_completion_tokens` to bound total generated output while retaining `grammar: "flint"`:
+
+```json
+{
+  "model": "flint",
+  "messages": [{"role": "user", "content": "Hello"}],
+  "grammar": "flint",
+  "max_tokens": 2048,
+  "stream": false
+}
+```
+
+The cap includes reasoning and answer or tool-call tokens. Reaching it can return `finish_reason: "length"` before an answer or tool call is complete. Non-null `max_completion_tokens` takes precedence over `max_tokens`. Omitting both permits generation through the remaining context; the terminal chat token default is separate.
+
+This version has no separate reasoning-only allowance. Unsupported fields such as `reasoning_effort`, `thinking_token_budget`, `reasoning_budget_tokens` and `chat_template_kwargs` are removed and logged. Nonempty custom stop strings cannot be combined with Flint grammar. Token limits must use integer JSON values.
+
+See the pinned [request allowlist and validation](https://github.com/recursive-oss/rec/blob/8af99abaf50b33903147d89eed91d1bb3ac642dd/engine/src/rec_mlx/server.py#L134-L224) and [output-limit handling](https://github.com/recursive-oss/rec/blob/8af99abaf50b33903147d89eed91d1bb3ac642dd/engine/src/rec_mlx/server.py#L249-L262).
+
 ## Download the weights separately
 
 With the [Hugging Face CLI](https://huggingface.co/docs/huggingface_hub/guides/cli) installed: